/*
    SUSAN® - Sole of Unix Save ANything

   
      Copyright (C) 2011-2016 Skyatlas Co. LTD

   

   
*/
/*
 * Kern Sibbald, MM, MMI
 */
/**
 * @file
 * Higher Level Device routines.
 * Knows about Susan tape labels and such
 *
 * NOTE! In general, subroutines that have the word
 * "device" in the name do locking. Subroutines
 * that have the word "dev" in the name do not
 * do locking.  Thus if xxx_device() calls
 * yyy_dev(), all is OK, but if xxx_device()
 * calls yyy_device(), everything will hang.
 * Obviously, no zzz_dev() is allowed to call
 * a www_device() or everything falls apart.
 *
 * Concerning the routines dev->r_lock()() and BlockDevice()
 * see the end of this module for details.  In general,
 * blocking a device leaves it in a state where all threads
 * other than the current thread block when they attempt to
 * lock the device. They remain suspended (blocked) until the device
 * is unblocked. So, a device is blocked during an operation
 * that takes a long time (initialization, mounting a new
 * volume, ...) locking a device is done for an operation
 * that takes a short time such as writing data to the
 * device.
 */

#include "include/susan.h" /* pull in global headers */
#include "stored/bsr.h"
#include "stored/stored.h" /* pull in Storage Daemon headers */
#include "stored/device.h"
#include "stored/device_control_record.h"
#include "stored/jcr_private.h"
#include "stored/match_bsr.h"
#include "lib/edit.h"
#include "include/jcr.h"
#include "lib/berrno.h"

namespace storagedaemon {

/**
 * This is the dreaded moment. We either have an end of
 * medium condition or worse, an error condition.
 * Attempt to "recover" by obtaining a new Volume.
 *
 * Here are a few things to know:
 *  dcr->VolCatInfo contains the info on the "current" tape for this job.
 *  dev->VolCatInfo contains the info on the tape in the drive.
 *    The tape in the drive could have changed several times since
 *    the last time the job used it (jcr->VolCatInfo).
 *  dcr->VolumeName is the name of the current/desired tape in the drive.
 *
 * We enter with device locked, and
 *     exit with device locked.
 *
 * Note, we are called only from one place in block.c for the daemons.
 *     The btape utility calls it from btape.c.
 *
 *  Returns: true  on success
 *           false on failure
 */
bool FixupDeviceBlockWriteError(DeviceControlRecord* dcr, int retries)
{
  char PrevVolName[MAX_NAME_LENGTH];
  DeviceBlock* block;
  char b1[30], b2[30];
  time_t wait_time;
  char dt[MAX_TIME_LENGTH];
  JobControlRecord* jcr = dcr->jcr;
  Device* dev = dcr->dev;
  int blocked = dev->blocked(); /* save any previous blocked status */
  bool ok = false;

  wait_time = time(NULL);

  Dmsg0(100, "=== Enter FixupDeviceBlockWriteError\n");

  /*
   * If we are blocked at entry, unblock it, and set our own block status
   */
  if (blocked != BST_NOT_BLOCKED) { UnblockDevice(dev); }
  BlockDevice(dev, BST_DOING_ACQUIRE);

  /* Continue unlocked, but leave BLOCKED */
  dev->Unlock();

  bstrncpy(PrevVolName, dev->getVolCatName(), sizeof(PrevVolName));
  bstrncpy(dev->VolHdr.PrevVolumeName, PrevVolName,
           sizeof(dev->VolHdr.PrevVolumeName));

  /* Save the old block and create a new temporary label block */
  block = dcr->block;
  dcr->block = new_block(dev);

  /* Inform User about end of medium */
  Jmsg(jcr, M_INFO, 0,
       _("End of medium on Volume \"%s\" Bytes=%s Blocks=%s at %s.\n"),
       PrevVolName, edit_uint64_with_commas(dev->VolCatInfo.VolCatBytes, b1),
       edit_uint64_with_commas(dev->VolCatInfo.VolCatBlocks, b2),
       bstrftime(dt, sizeof(dt), time(NULL)));

  Dmsg1(050, "SetUnload dev=%s\n", dev->print_name());
  dev->SetUnload();
  if (!dcr->MountNextWriteVolume()) {
    FreeBlock(dcr->block);
    dcr->block = block;
    dev->Lock();
    goto bail_out;
  }
  Dmsg2(050, "MustUnload=%d dev=%s\n", dev->MustUnload(), dev->print_name());
  dev->Lock(); /* lock again */

  dev->VolCatInfo.VolCatJobs++;           /* increment number of jobs on vol */
  dcr->DirUpdateVolumeInfo(false, false); /* send Volume info to Director */

  Jmsg(jcr, M_INFO, 0, _("New volume \"%s\" mounted on device %s at %s.\n"),
       dcr->VolumeName, dev->print_name(),
       bstrftime(dt, sizeof(dt), time(NULL)));

  /*
   * If this is a new tape, the label_blk will contain the
   *  label, so write it now. If this is a previously
   *  used tape, MountNextWriteVolume() will return an
   *  empty label_blk, and nothing will be written.
   */
  Dmsg0(190, "write label block to dev\n");
  if (!dcr->WriteBlockToDev()) {
    BErrNo be;
    Pmsg1(0, _("WriteBlockToDevice Volume label failed. ERR=%s"),
          be.bstrerror(dev->dev_errno));
    FreeBlock(dcr->block);
    dcr->block = block;
    goto bail_out;
  }
  FreeBlock(dcr->block);
  dcr->block = block;

  /*
   * Walk through all attached jcrs indicating the volume has changed
   */
  Dmsg1(100, "Notify vol change. Volume=%s\n", dev->getVolCatName());
  for (auto mdcr : dev->attached_dcrs) {
    JobControlRecord* mjcr = mdcr->jcr;
    if (mjcr->JobId == 0) { continue; /* ignore console */ }
    mdcr->NewVol = true;
    if (jcr != mjcr) {
      bstrncpy(mdcr->VolumeName, dcr->VolumeName, sizeof(mdcr->VolumeName));
    }
  }

  /* Clear NewVol now because DirGetVolumeInfo() already done */
  jcr->impl->dcr->NewVol = false;
  SetNewVolumeParameters(dcr);

  jcr->run_time += time(NULL) - wait_time; /* correct run time for mount wait */

  /* Write overflow block to device */
  Dmsg0(190, "Write overflow block to dev\n");
  if (!dcr->WriteBlockToDev()) {
    BErrNo be;
    Dmsg1(0, _("WriteBlockToDevice overflow block failed. ERR=%s"),
          be.bstrerror(dev->dev_errno));
    /* Note: recursive call */
    if (retries-- <= 0 || !FixupDeviceBlockWriteError(dcr, retries)) {
      Jmsg2(jcr, M_FATAL, 0,
            _("Catastrophic error. Cannot write overflow block to device %s. "
              "ERR=%s"),
            dev->print_name(), be.bstrerror(dev->dev_errno));
      goto bail_out;
    }
  }
  ok = true;

bail_out:
  /*
   * At this point, the device is locked and blocked.
   * Unblock the device, restore any entry blocked condition, then
   *   return leaving the device locked (as it was on entry).
   */
  UnblockDevice(dev);
  if (blocked != BST_NOT_BLOCKED) { BlockDevice(dev, blocked); }
  return ok; /* device locked */
}

void SetStartVolPosition(DeviceControlRecord* dcr)
{
  Device* dev = dcr->dev;
  /* Set new start position */
  if (dev->IsTape()) {
    dcr->StartBlock = dev->block_num;
    dcr->StartFile = dev->file;
  } else {
    dcr->StartBlock = (uint32_t)dev->file_addr;
    dcr->StartFile = (uint32_t)(dev->file_addr >> 32);
  }
}

/**
 * We have a new Volume mounted, so reset the Volume parameters
 *  concerning this job.  The global changes were made earlier
 *  in the dev structure.
 */
void SetNewVolumeParameters(DeviceControlRecord* dcr)
{
  JobControlRecord* jcr = dcr->jcr;
  if (dcr->NewVol && !dcr->DirGetVolumeInfo(GET_VOL_INFO_FOR_WRITE)) {
    Jmsg1(jcr, M_ERROR, 0, "%s", jcr->errmsg);
  }
  SetNewFileParameters(dcr);
  jcr->impl->NumWriteVolumes++;
  dcr->NewVol = false;
}

/**
 * We are now in a new Volume file, so reset the Volume parameters
 *  concerning this job.  The global changes were made earlier
 *  in the dev structure.
 */
void SetNewFileParameters(DeviceControlRecord* dcr)
{
  SetStartVolPosition(dcr);

  /* Reset indicies */
  dcr->VolFirstIndex = 0;
  dcr->VolLastIndex = 0;
  dcr->NewFile = false;
  dcr->WroteVol = false;
}

/**
 *   First Open of the device. Expect dev to already be initialized.
 *
 *   This routine is used only when the Storage daemon starts
 *   and always_open is set, and in the stand-alone utility
 *   routines such as bextract.
 *
 *   Note, opening of a normal file is deferred to later so
 *    that we can get the filename; the device_name for
 *    a file is the directory only.
 *
 *   Returns: false on failure
 *            true  on success
 */
bool FirstOpenDevice(DeviceControlRecord* dcr)
{
  Device* dev = dcr->dev;
  bool ok = true;

  Dmsg0(120, "start open_output_device()\n");
  if (!dev) { return false; }

  dev->rLock();

  /* Defer opening files */
  if (!dev->IsTape()) {
    Dmsg0(129, "Device is file, deferring open.\n");
    goto bail_out;
  }

  DeviceMode mode;
  if (dev->HasCap(CAP_STREAM)) {
    mode = DeviceMode::OPEN_WRITE_ONLY;
  } else {
    mode = DeviceMode::OPEN_READ_ONLY;
  }
  Dmsg0(129, "Opening device.\n");
  if (!dev->open(dcr, mode)) {
    Emsg1(M_FATAL, 0, _("dev open failed: %s\n"), dev->errmsg);
    ok = false;
    goto bail_out;
  }
  Dmsg1(129, "open dev %s OK\n", dev->print_name());

bail_out:
  dev->Unlock();
  return ok;
}

/**
 * Position to the first file on this volume
 */
BootStrapRecord* PositionDeviceToFirstFile(JobControlRecord* jcr,
                                           DeviceControlRecord* dcr)
{
  BootStrapRecord* bsr = NULL;
  Device* dev = dcr->dev;
  uint32_t file, block;
  /*
   * Now find and position to first file and block
   *   on this tape.
   */
  if (jcr->impl->read_session.bsr) {
    jcr->impl->read_session.bsr->Reposition = true;
    bsr = find_next_bsr(jcr->impl->read_session.bsr, dev);
    if (GetBsrStartAddr(bsr, &file, &block) > 0) {
      Jmsg(jcr, M_INFO, 0,
           _("Forward spacing Volume \"%s\" to file:block %u:%u.\n"),
           dev->VolHdr.VolumeName, file, block);
      dev->Reposition(dcr, file, block);
    }
  }
  return bsr;
}

/**
 * See if we can Reposition.
 *
 * Returns: true  if at end of volume
 *          false otherwise
 */
bool TryDeviceRepositioning(JobControlRecord* jcr,
                            DeviceRecord* rec,
                            DeviceControlRecord* dcr)
{
  BootStrapRecord* bsr;
  Device* dev = dcr->dev;

  bsr = find_next_bsr(jcr->impl->read_session.bsr, dev);
  if (bsr == NULL && jcr->impl->read_session.bsr->mount_next_volume) {
    Dmsg0(500, "Would mount next volume here\n");
    Dmsg2(500, "Current position (file:block) %u:%u\n", dev->file,
          dev->block_num);
    jcr->impl->read_session.bsr->mount_next_volume = false;
    if (!dev->AtEot()) {
      /* Set EOT flag to force mount of next Volume */
      jcr->impl->read_session.mount_next_volume = true;
      dev->SetEot();
    }
    rec->Block = 0;
    return true;
  }
  if (bsr) {
    /*
     * ***FIXME*** gross kludge to make disk seeking work.  Remove
     *   when find_next_bsr() is fixed not to return a bsr already
     *   completed.
     */
    uint32_t block, file;
    /* TODO: use dev->file_addr ? */
    uint64_t dev_addr = (((uint64_t)dev->file) << 32) | dev->block_num;
    uint64_t bsr_addr = GetBsrStartAddr(bsr, &file, &block);

    if (dev_addr > bsr_addr) { return false; }
    Dmsg4(500, "Try_Reposition from (file:block) %u:%u to %u:%u\n", dev->file,
          dev->block_num, file, block);
    dev->Reposition(dcr, file, block);
    rec->Block = 0;
  }
  return false;
}

} /* namespace storagedaemon */
